Origen

To engage in casting aspersions is almost literally mud-slinging. Aspersion originally meant ‘sprinkling water or other liquid on someone’, especially in baptism, and came from Latin spargere ‘to sprinkle’ (the root of disperse (Late Middle English) ‘scatter widely’, and intersperse (mid 16th century) ‘sprinkle between’). Sprinkling a person with water developed into the idea of spattering them with something less pleasant, such as mud or dung. This in turn led to the notion of soiling a person's reputation by making false and damaging insinuations against them. See also slur